Having one option in many files is quite normal and common. I'm not great fan of issuing warnings for a valid and documented use of a feature just because someone somewhere might use it by mistake and get unexpected resulst (hi, gcc!).

May be only as a note or only for high values of @@log_warnings... But then it won't serve its purpose — it won't help unexperienced users. Those who know how to increase the log verbosity, they also know that an option may be present in many files and they know how to use mysqld --help --verbose and my_print_defaults --mysqld.

The purpose is not just for "unexperienced users". What about experienced users trying to quickly solve problems for customers, for instance? With more and more config files (mariadb-enterprise.cnf, tokudb.cnf, galera.cnf,...) and locations (...), I personally think this is an excellent request.

I'm fine with it being logged for log_warnings=2+, fwiw. I really like that approach.

Thank you for your consideration.

Experienced users can run my_print_defaults --mysqld.
But ok, it's a valid feature request.

I have removed the fixVersion for this task as it is one of 5.5, 10.1, 10.2, 10.3, which are EOLed.

Please add a new fixVersion if you plan to work on this task for a not EOLed versions.